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Walther I can not see any information on these regulators. They all look like the real deal. And I do not know what diafram they are using, you must be able to replace it later if necessary. Lets see what TN's opinion are. Phone Jacques at SMART 0123773430 and see what he has got, ask about the pressure rate and diafram availability.

To state the theory for interest sake: A N/A car have a negative pressure in the intake manifold as the cylinder "suck" the air in. As this negative pressure increase the oe fuel pressure regulators will increase the pressure about 20% to help the fuel supply at revs.

In the case of a turbo car this is turned around as there as only a negatve pressure at idling and at part throttle cruising. When accelerating there are a pressure in the manifold and the oe regulator will decrease the fuel pressure. So we fit increasing rate FPR to turbo cars. Common is a 1:1 ratio. That means if your Bosch system is normally working at 3 bar fuel pressure, The fuel pressure will increase to 4 bar when the boost pressure goes to 1 bar.

There are 2:1 regulators available for racing cars and they are used to increase fuel supply in these cars that already use very large injectors (750 - 1600 cc/min) This is not good on a road car as it is very difficult to tune.
 

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I don't understand this...

You recently bought the car, did it work fine when you bought it?

What is causing the problems now?
 

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Discussion Starter #4
The car is fine I drove back with no problems at all. But I am going to have to do this modification of putting the fuel pressure to the front. There car does loose fuel pressure at times and like Hennie and Carlo said this would solve it. Hennie just never had time to do it. He is extremely busy at work and it is understandable.

It would just be better for the long run and lifetime of the motor. I only want the best for my baby!

Thank you for your nice reply Corrie. I'm learning more and it is all making better sense to me. I can add that a turbocharged twin spark is a totally different ball game than driving an uno turbo what I was use to.
 

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I had both as well and must admit the smoothness if the engine and traction of the suspension change the character away from the hooligan boy racer, to a serious, civilized car.
 

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Discussion Starter #6
Corrie you couldn't of said it better. The uno turbo is a fast straight line car. That's all I can say about it. Uncomfortable as hell. But the Alfa is something totally different. Its not the speed and racing I am after but in fact it is the comfort and style. The feeling of driving a real motor car with added power as a bonus! An Alfa just adds that extra passion words cannot describe.
 

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Discussion Starter #8
Lol very soon!!! As soon as I get my new plates on the 146 some nice pics will be taken!
 

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All of them will work but they are not the best out there.
Like I suggested over the phone ask the person who will be doing the dyno work for you he should know where in your vicinity you can get a proper FPR.
Like we discussed just make sure that it is not one with a Plastic diaphragm since they seem to be unstable.

I should be doing the fuel pump mod this weekend or early next week and will post a full description of what should be done + picks for all the people who are interested especially since it will help higher in the rpm range on na cars as well. And the units are becoming old and this may be a cheaper fix for a lot of people.
 

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With regard to Fuel Pressure Regulators:

An OE FPR will also increase fuel pressure at the equal rate of boost added.

In an Adjustable Rising Rate Fuel Presure Regulator the pressure increase ratio is actually adjusted and in some models the onset point as well. Therefor it is not only a FRP with non standard 1:1 ratio.

These were popular when only smaller increases in air volume intake were added to a factory engine in conjuntion with other even cruder methods like constantly running cold start enrichment injectors by sending a false signal to the ECU from the engine coolant temp sensor. This was mostly to curb cost and as a result of commercially unavailable programmable engine management either standalone or additional.

Remember increasing fuel pressure will increase fuel delivery over the entire operating cycle in proportion to the square root of the new pressure devided by the original pressure.

Your fuel delivery system will increase its supplied volume by 7.21% when increasing fuel pressure from 43.5 PSi to 50 PSi - as an example - resulting in a vehicle literally 7.21% less fuel efficient - all other factors remaining constant (which naturally is hardly ever the case).

Further more remember that the flow of a fuel pump is inversely proportional to the pressure applied. A fuel pump might supply 8 BAR pressure when plugged but as pressure decreases flow increases until equilibrium is achieved.

The reason for this comment is to circle back to TN's comment that the only reason you are touching the FPR is to get one of higher quality which should hopefully deliver higher consistancy.

Other methods of tuning is achieved but the FRP and Fuel pump consistancy is key in this application, since as can be seen from the example a drop in fuel pressure has a very real effect on AFR.

:thumbs:
 

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Jaco I agree when it is turbo engine factory car. We change the FPR when we turbo an previously NA engine.

With a oe NA engine FPR, the dyno tuner will soon have the injectors operate past the 80% duty cycle and still not have enough fuel for the half the power needed.

I believe TN refered to the 3 FPR examples that Wildcard asked about. As for the quality of the FPR, it is all about the diafram used. The plastic ones do not cope well when the fuel supply change rapidly as under acceleration. Their service life is also suspect.
 

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Yes Corrie i referred to the 3 units.
Ok there’s a lot of theories out there all well founded but i am solely referring to the Alfas with the fpr in the pump unit and oe management at this stage so could not care less about other applications.
Firstly we learned in school that pressure in a system is the same no matter where you measure.
That is 100% until you start draining liquid from the furthest point -injectors in this case).
The rating on the fpr located in the tank is 3.5 bar but we have never measured more than 3 bar on a oe Alfa.
At idle it is in the region of 2.8 and at WOT it will drop to 2bar id the system is old even less.
By moving the fpr to sit behind the injectors we managed 3bar and 2.8 bar at idle without a problem which already helps a lot with spray patterns considering that the flow rate of most injectors are measured at 3bar.
This shows that the injectors in our cars are not optimally used to begin with.

On the 156 2.5 turbo as an example we moved the fpr to the front and ran a static 3bar pressure with amazing results and absolutely no problems.
Later on we connected the reference pipe of the fpr and consumption with normal driving improved thanks to the lower pressure at idle. So using a variable rate fpr can actually improve consumption although marginally.
At 0.5 bar boost the pressure will raise to 3.5 bar for argument sake so that’s an added safety margin.
 

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get an iPad 2...best thing ever!
 

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Won’t help the main problem was sitting in the garden after a couple of beers typing on the phone in the dark.:cheese:
 
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get an iPad 2...best thing ever!
So you got yours then Guili,

You gonna download the daignostics app :cheese: (costs about R380) but certain cables are needed to hook your car up to the iPad2 app
 
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